Problem About "Get" and "Set" Methods

Unity Engine
1

Hello guys,

I have problem about encapsulation. I have learned that in Java and as far as I know it works the same way in C# but in Unity It does not work. I will show you.

<------------------------------------------------------------------------>

using UnityEngine;
using System.Collections;

public class AnotherClass
{
private int apple;

public void setApple(int app)
{
apple = app; // I am given an error message saying: “Apple does not exist in the current
context.”
}

public int getApple()
{
return apple; //Same here.
}
}

<------------------------------------------------------------------------>

I am just trying to apply encapsulation but I am given these error messages. I want to create an “AnotherClass” instance and want to change the “apple” value via “setApple” method. I do this in java and C# without having any problems but in Mono I am given this error message: “Apple does not exist in the current context.”

Can you please tell me what problem is ?

2

Works fine for me.

using UnityEngine;
using System.Collections;

public class AnotherClass {
   private int apple;
   
   public void setApple(int app) {
     apple = app;
   }
   
   public int getApple() {
     return apple;
   }
}

Was able to instantiate an object from the class in another script.

using UnityEngine;
using System.Collections;

public class Blah : MonoBehaviour {
   void Start () {
     AnotherClass apple = new AnotherClass();
     apple.setApple(5);
   }
}
3

I feel the need to point out that C# has a grammar structure for more easily implementing properties.

using UnityEngine;
using System.Collections;

public class AnotherClass {
   private int m_apple;
  
   public int Apple {
     get {
       return m_apple;
     }
    
     set {
       m_apple = value;
     }
   }
}

Using them is like this.

using UnityEngine;
using System.Collections;
public class Blah : MonoBehaviour {
  void Start () {
    AnotherClass apple = new AnotherClass();
    apple.Apple = 5;
   
    Debug.Log(apple.Apple.ToString());
  }
}
4

Thank you for your answer. I just restarted unity then it was fixed… I think that was a bug and I am trying to solve this for one hour :slight_smile:

5

I have seen this before but did not understand actually. As far as I understand both code format make the same job but syntax is different right?

6

More or less. Stackoverflow points out that its little more than syntatic sugar. Most likely to reduce clutter.

http://stackoverflow.com/questions/13162867/c-sharp-properties-versus-accessor-methods

1 Like
7

Some good helpful information about Properties and Methods in here. I think I need to check and work on this later.
http://stackoverflow.com/questions/2544707/difference-between-property-and-method

1 Like
8

More syntactic sugar: when using properties, consider the auto-implemented properties.

public int Apple {
   get {
      return m_apple;
   }

   set {
      m_apple = value;
   }
}

Is the same as:

public int Apple { get; set; }

And won’t break your code if you suddenly need to implement some logic.

9

A little point to remember in Unity though:

Properties will not appear in the editor and cannot be set in the editor.

Unity ignores them for some reason (can’t know what will happen when the get and set methods are called I suppose)

10

It’s because properties are methods, they don’t necessarily have data behind them.

Example:

public class Vector2
{
  
    private float _x;
    private float _y;
  
    public float X
    {
        get { return _x; }
        set { _x = value; }
    }
  
    public float Y
    {
        get { return _y; }
        set { _y = value; }
    }
  
    public float Magnitude
    {
        get { return Math.Sqrt(_x * _x + _y * _y); }
        set
        {
            var l = Math.Sqrt(_x * _x + _y * _y);
            _x = value * _x / l;
            _y = value * _y / l;
        }
    }
}

What is Magnitude? How do we display Magnitude? How is Magnitude serialized? Updating Magnitude sets 2 other fields which reflects a change in those properites.

The inspector displays the data that can be serialized on the object. And that data is represented as the fields.

Of course inspectors CAN show properties, you write a custom inspector to do so, so that way you decide what properties show and what don’t.

2 Likes